Power regulating means for typewriters



Oct. 31, 1950 J. PETZ POWER REGULATING MEANS FOR TYPEWRITERS Filed Dec. 15, 1946 2 eets-Sheet 1 Oct. 31, "1950 J. L. PETZ 2,528,450

POWER REGULATING MEANS FOR TYPEWRITERS Filed' Dec. 13, 1946 2 Sheets-Sheet 2 Patented a. 31, 1950 UNITED STATES PATENT OFFICE rowan REGULATING MEANS FOR TYPEWRITERS John. L. Petz, Poughkeepsie, N. Y., assignor to International Business Machine Corporation,

New York, N. Y., a corporation of New York I Application December 13, 1946, Serial No. 716,159

12 Claims.

between the parts operated, such as the type bars.

An object is to provide an improved operating mechanism for typewriting machines using type bars mounted in'the well known wire segment.

An object is. to provide an improved adjustable type bar action. I

An object isto provide an improved non-repeat mechanism for power operated typewriters.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings: 7 I

Fig. 1 is a vertical section showing a power mechanism for typewriters constructed in accordance with the present invention.

Fig. 2 is a vertical section showing the key and certain other parts in operated position.

Fig. 3 is a vertical section showing the power mechanism in fully operated position.

Fig. 41 is a vertical section showing the key depressed to illustrate the action of the. nonrepeat mechanism. I

Fig. 5 is a detail section showing the manner in which the stroke of the power operating device is adjusted.

In Fig. 1 the reference numeral l0 designates one of the character keys of the typewriter which key is pivoted on the cross rod ll. Only one key is shown but it will be understood that there are as many keys lll as'there are characters to by the sub-levers which operate'the type bars mustv necessarily vary in length and also must be bent varying degrees to make the proper connections to the type bars.

Each type bar I2 is operated by a'power device under control of a key [0 which power device includes a lever [3 having a link connection l4 to the type bar [2. Rocking of the lever 13 in a clockwise direction (Fig. 1) draws the linkjl4 to the right, thereby actuating the type bar l2 through an arc of approximately to the position of Fig! 3 to effect an impression on a work sheet carried by the usualplaten 15. The levers IS-are not pivoted on fixed pivots, as is usually the custom with sub-levers commonly used in the,

art,. but nieansis provided to enable adjustment of the leverage ratios of the levers 13 to vary the blow according to'the area of type face.

I Each of the levers I3 is formed with a curved slot [3a which embraces a pivot wire [6 supported by a cross bar IT. The cross bar I! is vertically slotted to accommodate the levers l3 and the teeth formed by these slots are also slotted parallel with the longer edges of bar I! to accommodate the pivot wire 16. Thus the bar I! not only supports the levers l3, butalso acts as a guide comb to space them the proper distances apart.

Pivotally mounted at 13b on the lever I3- (Fig. l) is an L-shaped cam I8 having a serrated tread portion'18a designed to cooperate with a power roller 19 which is rotatable in the direction-of the arrow (Fig. 1). The cam I8 is provided with a restoring spring 20 which is anchored to an ear formed in the cam l8 and to a lug formed in the lever l3. The spring 20 urges the cam 18 in a counterblockwise direction but, in the normal position of Fig. 1, rotation of the cam counterclockwise is prevented by a cam operating .finger 2| which is pivotally slidably mounted on a stud l-3d carried by an extension l 3e formedin the lever I3. A spring 22 anchoredto an ear formed in the finger 2| and to an ear formed in the extension l3e tends to rock the finger 2| clockwise, holding. said finger against a lug I 3f formed in the extension 13c, the spring 2,2also maintaining the stud l3d at the right. hand end of the slot in the finger 2i. 7 The cam 18 has an extension [82) in engagement with ashoe' portion in the form of a bent-overlug 2 la in thefinger 2!. The latter also has a bent-over'lug 2Ib which just clears a long curved finger i (la formed in the key [0.

The finger 2! has two functions. One function of the finger is to act as an interposer between the key ,ID and the extension [8b to enable the key to rock the cam I8 clockwise (Fig. 1) far enough for the serrated portion Isa in the cam to be gripped by the power roller I9 when the key IE3 is depressed. The power roller then rotates the cam i8 clockwise and, owing to the shape of the cam IS, the lever I3 will likewise be actuated in a clockwise direction, thereby operating the type bar I2 to the position of Fig. 3.

The cam lever I3 and the cam I8 assume the positions shown in Fig. 3 when the cam 58 is operated as far as it can go by the power roller I9. As usual in typewriting machines, the last few degrees of movement of the type bar I2 are effected by inertia causing the cam I8 to be pulled slightly clear of the power roller, considering the position of the parts as in Fig. 3. This allows the spring 29 to rock the cam I8 back to the position of Fig. 1, with respect to the lever I3, as shown by dotted lines in Fig. 3, before said lever starts its return stroke, or at least before said lever has gone very far in restoring.

In order to regulate the force exerted by the upper end of each lever I3 under the stimulus of the cam I8, provision ismade for individually varying the fulcrum point of each lever. For this purpose the lower end of each lever I3 is provided with aseries of notches I39 which are arranged in-an arc of a circle. Cooperating with one of the notches is a pin 23a carried by an L.- shaped plate 23. The latter also has a series of notches 23b which are arranged different radial distances from the pin 23a for a purpose which will be made clear hereinafter.

For those type bars of an ordinary machine which are near the center of the segment and for which the corresponding levers I3 are shortest, the pins 23a may be positioned in one of the upper notches I3g as in Fig. 1 and will act as a fulcrum point for the associated levers. Thus in Fig. 1 the pin 23a is shown in the top notch |3g which is the shortest distance from the guide rod I6 and from the stud I3b. It is clear that, with the operating force of the cam I8 applied to the stud I31) and the lever I3 pivoting on the stud 23a, the upper end of the lever I3 will be thrown to the right the maximum amount when the cam I8 is operated by power roller I9 in the manner above described.

In the case of the end type bars on the segment, the levers I3 necessarily will be longer and bent diiferent extents to accommodate the end type bars. Accordingly, the pins 23a for such type bars may be located in one of the lower notches I3g, whereby the movement of the stud I3b a fixed arcuate distance will have less eifect on the upper ends of the levers I3. However, such levers, being longer to compensate the higher level of the end type bars, will have their upper ends operated the same extent as the central type bars. The rod I6 acts purely as a guide for the levers I3 and prevents them and members 23 from dropping downwardly. Each lever I3 and the corresponding type bar I2 is restored by means of a spring 24 anchored to the lower end of the lever I3.

The notches 2329 are seated on the edge of a fulcrum bar 25 which extends across the machine, the plates 23 being received in slots formed in a Z-shaped comb bar 26 secured to the bar 25 and to the bar II. The main purpose of the notches 23b is to provide a means for adusting the clearance between each cam I3 and the power roller I9 when the parts are in the position of Fig. 1 and for this reason the notches are located very slightly different radial distances from the p n 23a. By disengaging the plates 23 from the fulcrum bar ZE'against the tensions of springs E i and swinging the plates up or down and then engaging the proper notches with the fulcrum bar 25, the pins 23a may be adjustably positioned to right or left'and thereby move the levers i3 and the cams I8a nearer or further away from the power roller I9 as needed. When adjusted in this manner, the upper ends of levers i3 rock slightly about a bumper bar 2? in the form of a resilient strip carried by a channel shaped me. ber 23 supported by the side frames of the machine.

The adjustability of the clearance between the cams I8 and power roller I9 makes it possible to vary the blow of the type bars to suit the area of type face of the characters printed. It has been found that, when the clearance space is at a minimum, the actuation of cam 58 by key It will engage the cam with the power roller I9 at the extreme upper end of the serrated tread 53a and the cam will coact with the power roller for a longer period than when the clearance space is large. It has been found that increasing the clearance between the cam I8 and the power roller 5 9 has the elfect of increasing the blow of the type. It is believed that this is due tothe fact that, with an increase in clearance between the cam I 8 and the power roller I9, the cam must be rotated further before it engages the power roller and consequently starts the type bar at a higher rate of acceleration owing to the increased steepness of the cam at a point beyond the normal engaging position which is at the upper end of the tread Illa.

The foregoing description has assumed that the arms of the type bars I2 to which the links I4 are pivoted are of equal lengths, as would ordinarily be the case in conventional typewriters, particularly of the type employing a wire segment. In such a machine the adjustment of the pins 23a in the notches I30 may be used as a means of compensating for the varying lengths and positional diiferences of the levers I3, and the adjustment of the notches 232) may be used as a means of varying the blow of the type bars. It is possible, however, to use other means for compensating the different lengths of the levers I3 and their positional differences in the machine which necessitates bending them to such an eX- tent as to affect their leverageratios. This may be done by making the arms of the type bars IE to which the links I4 are connected of varying lengths. For example, those type bars in the center of the machine, which necessarily are operated by the shorter levers I3, willhave shorter arms, whereas the type bars at the ends of the segment will have longer arms, whereby the driving ratios of all of the type bars I2 with reference to the levers I3 will be constant when the levers I3 are actuated a constant angular distance. In such a machine the adjustment of .pins 28a may be used to give a coarse adjustment of the blow and the adjustment of the notches 231) used to obtain a fine adjustment of the blow.

The bar 26, a leaf spring plate 29, and a spring tension comb plate 30 are secured to the cross bar II by means of common screws. The spring plate 29 is formed like a comb, the teeth of which engage extensions IEIb formed in the keys 5 I and the spring tension plate 30 is formed with a series of teeth bent as shown in Fig. 1 to form bearings for the teeth 29 on the spring comb plate. This construction enables a great amount of flexibility to be obtained from the teeth of the spring plate 29while maintaininglenough tension to restore the key 10. i

The members 2! which are interposedbetween the extension Illa of the-keys a nd theextensions 18b of the cam I8 also function to preven-t repeated operation of the cam l8 in theaevent that thekey lilis held depressed. 1 H

When the key Hlis depressed and released. immediately the member 2|, as described above, merely rocks the cam I8 far enough to engage the power'roller I9 and is immediately restored to the position of Fig. 3 by the spring 22." The op.- eration of the lever 13 by the cam l8 causes the extension [36 to travel clockwise in an arc of a circle, with the pin 23a as a center, to the position ofFig. 3 in'which the lug 2lb'on the member 2! occupies a position to the right and belowthe end of the extension 'lllcttIIiW-hen th'l'eter l3 is restored-by spring 24,, the member 2! will be permitted to move, without obstruction by the extension Ilia, back to the position of Fig. 1, owing to the clearance which is prov-ided between the lug 2lb and the'extension Illa. -If, however; the key it! is held depressed asshown insolid lines (Fig. a), the end of the extension lilqwill remain in the path of mQVQmBhtof the. lug Zlbqwiththe result that such lug will. b engaged by theextension and held as shown in Fig. 4, sliding on the stud l3d against the tension 'of the spring 22. Thus, when the lever I3 is fully restored, the member 2| will have the-position shown in Fig. 4, preventing a second operation of the cam 18 until the key In is released. As soonas the key is released the extension lfla will clear the lug 2 l b and allow the spring 22 to snap said lug back underneath the extension as shown in Fig.1.

The lugs I engage a universal bar 3! common to all of the type bars. This universal bar is and is operated each time a type bar is actuated.

The universal bar is restored by a spring (not shown) and may be used to actuate the usual inking ribbon mechanism.

While there have been shown and described and pointed out the fundamental novel features of the invention, as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the-invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims. I v

What is claimed is:

1. In a power mechanism having a power roller, a cam, a cam lever, and means to render the cam operable by the power roller to actuate said cam lever; in combination with said cam lever, means to vary the leverage ratio of said lever, comprising a fulcrum element having a pin pivotally engageable with said lever at different radial distances from the end of one arm of said lever.

2. In a power operated typewriter, a power actuator, a power device operable by said actuator including a rock lever and a coupling element normally clear of the power actuator but engageable therewith to cause the power device to be actuated by said actuator; and a fulcrum member having a pivot to said lever which pivot is adjustably shiftable along an arm of said lever to vary the leverage ratio of said lever and having a stationary pivot and movable relative to said stationary pivot and transversely of said shifting movement to vary the clearance between said actuator and coupling element.

3. In a power-operated typewriter, a fixed frame member, a main power actuator, a power device including a rock lever and, a coupling element normally clear of the actuator for operatively coupling the rock lever to the actuator, and an adjustable fulcrum for said lever comprising a plate having a pin pivotally connected to said lever and having a series of notches at different radial distances from said pin, a selected one of said notches being pivotally engaged by said frame member to predetermine the clearance between the coupling element and said actuator.

4. Ina power-operated typewriter, a power actuator, a device capable of being coupled to the power actuator including a rock lever having a guide slot and provided-with a series of notches disposed along one arm thereof at different distances from said slot, a fulcrum plate having a pin. registering with a preselected one of said notches and serving as a fulcrum for said lever, said pin being normally positionable in any one of said notches to vary the leverage ratio of said lever, -a fixed guide element extending into said slot for guiding said lever in its rocking movement on said pin, and a spring for holding said pin in the selected notch. v

5. In a power operatedjtypewriter, a power actuator, a power device operable by said actuator including a rock lever and a coupling element normally clear of the power actuator but engageable therewith to cause the power device to be actuated by said actuator; and a fulcrum member pivotally connected at one end to said lever to act as a fulcrum therefor and having a relatively fixed pivot at its other end, said memher. being adjustably rockable on one of said pivots to vary the leverage ratio of the lever and adjustably rockable on the other of said pivots to varythe clearance of said member from said actuator.

6. The invention set forth in claim 5 characterized by the fact that the pivots for said fulcrum member comprise, in each case, a pin and a series of indexing notches receiving said pins, the clearance adjusting notches being different radial dis" tances from the ratio adjusting notches.

'7. In a power-operated typewriter, a power actuator, a power device operable by said actuator including a rock lever and a coupling element normally clear of the power actuator but engageable therewith to cause the power device to be actuated by said actuator, and means to vary the leverage ratio of said lever, said means including a plate having a possible pivotal relation to said lever at any one of a series of points along one arm of the lever and pivotally mounted to permit rocking of said plate to select the pivot point.

8. In a power-operated typewriter, a power a c- Y tuator, a power device operable by said actuator including .a rock lever and a coupling element normally clear of the power actuator but engageable therewith to cause the power device to be actuated by said actuator, and means to vary the clearance between said element and said actuator, said means including a plate pivotally connected to one arm of said lever and having a series of pivots at different radial distances from the pivotal connection of the plate to the arm', and fixed means cooperating with any selected one of said pivots.

9. In a power-operated typewriter, a main frame, a power actuator, a power device operable by said actuator including a rock lever and a coupling element normally clear of the power actuator but engageable therewith to cause the power device to be actuated by said actuator, and means for varying both the leverage ratio of said lever and the clearance of the element from the actuator, said means including a plate having shiftable pivotal connections to both an arm of said lever and said frame.

10. A power mechanism for typewriting machines comprising a power roller, a cam unit operable by the power roller and including a rockable cam frame and a cam rotatable in said frame by said roller to rock said frame, and means to fulcrum said frame and arranged to be shiftable difierent distances from the axis of rotation of the cam to vary the extent of rocking motion of the frame by the cam.

11. In a power operating mechanism for typewriters and other office machines, a fixed frame member, a main power actuator, a power device including a rock lever having a coupling element thereon normally clear of the actuator for operatively coupling the rock lever to the actuator, and a fulcrum member adjustably mounted at one end in said frame member and at its other end being pivotally adjustably connected to said rock lever for movement along said lever to vary the leverage ratio of said lever.

12. In a power operatingmechanism for typewriters and other ofiice machines, a fixed frame member, a main power actuator, a power device including a rock lever having a coupling element thereon normally clear of the actuator for operatively coupling the rock lever to the actuator, and a fulcrum plate adjustably movably connected to one arm of said lever to vary its leverage ratio and adjustably movably mounted on said frame member to vary the clearance between said coupling element and said actuator.

JOHN L. PETZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,227,846 Smathers May 29, 1917 1,428,851 Kurowski Sept. 12, 1922 1,643,057 Crumrine Sept. 20, 1927 1,661,710 Thompson Mar. 6, 1928 1,828,755 Von Reppert Oct. 27, 1931 1,924,140 Von Reppert Aug. 29, 1933 2,217,179 Mills Oct. 8, 1940 2,393,276 Von Reppert Jan. 1, 1946 

